[Generate] Small refactor (#15611)

src/transformers/generation_utils.py

@@ -525,12 +525,6 @@ class GenerationMixin:
             decoder_start_token_id = self._get_decoder_start_token_id(decoder_start_token_id, bos_token_id)
             return torch.ones((batch_size, 1), dtype=torch.long, device=self.device) * decoder_start_token_id
 
-    def _get_pad_token_id(self, pad_token_id: int = None, eos_token_id: int = None) -> int:
-        if pad_token_id is None and eos_token_id is not None:
-            logger.warning(f"Setting `pad_token_id` to `eos_token_id`:{eos_token_id} for open-end generation.")
-            pad_token_id = eos_token_id
-        return pad_token_id
-
     def _get_decoder_start_token_id(self, decoder_start_token_id: int = None, bos_token_id: int = None) -> int:
         decoder_start_token_id = (
             decoder_start_token_id if decoder_start_token_id is not None else self.config.decoder_start_token_id
@@ -1063,9 +1057,15 @@ class GenerationMixin:
 
         pad_token_id = pad_token_id if pad_token_id is not None else self.config.pad_token_id
         eos_token_id = eos_token_id if eos_token_id is not None else self.config.eos_token_id
+
         if eos_token_id is None and hasattr(self.config, "decoder"):
             eos_token_id = self.config.decoder.eos_token_id
 
+        if pad_token_id is None and eos_token_id is not None:
+            # special case if pad_token_id is not defined
+            logger.warning(f"Setting `pad_token_id` to `eos_token_id`:{eos_token_id} for open-end generation.")
+            pad_token_id = eos_token_id
+
         output_scores = output_scores if output_scores is not None else self.config.output_scores
         output_attentions = output_attentions if output_attentions is not None else self.config.output_attentions
         output_hidden_states = (
@@ -1075,11 +1075,6 @@ class GenerationMixin:
             return_dict_in_generate if return_dict_in_generate is not None else self.config.return_dict_in_generate
         )
 
-        if pad_token_id is None and eos_token_id is not None:
-            # special case if pad_token_id is not defined
-            logger.warning(f"Setting `pad_token_id` to `eos_token_id`:{eos_token_id} for open-end generation.")
-            pad_token_id = eos_token_id
-
         # 2. Define model inputs
         # inputs_tensor has to be defined
         # model_input_name is defined if model-specific keyword input is passed